Refined mapping of allele loss at chromosome 10q23-26 in prostate cancer

BACKGROUND: Allele loss of at least two segments in 10q, one mapping to the PTEN gene and one more distal were described in prostate cancer, with loss more frequent in advanced prostate cancer. METHODS: A 63 cM region from 10q23 to q26 was studied for allele loss (LOH) in 59 prostate cancer samples using a dense map of microsatellite markers. RESULTS: LOH of at least one marker in 10q was observed in 13/59 tumors. LOH increased with grade and stage. Detailed deletion mapping identified three regions of allele loss. The first region mapped to the site of the PTEN gene, the second is defined by loss of one marker, D10S1692, in one tumor, and the third is defined between markers D10S1757 and D10S587, including DMBT, with a subregion of approximately 1.2 Mb mapping between markers D10S209 and D10S1679, lost in one tumor. CONCLUSIONS: LOH at the PTEN gene is frequent but mutations in the remaining allele were not detected by SSCP-screening. There may be more than two tumor suppressor (TS) genes mapping more distal of PTEN. The site for these putative TS genes can now be mapped with a dense set of precisely localized markers in a larger series of advanced tumors.